scholarly journals Ba2VO4Br

IUCrData ◽  
2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Robert Haberkorn ◽  
Jessica Bauer ◽  
Guido Kickelbick

Single crystals of dibarium vanadate(V) bromide, Ba2VO4Br, were grown from a melt of Ba3(VO4)2and BaBr2. Ba2VO4Br crystallizes in the space groupPbcmand is isotypic with the structure of chlorspodiosite, Ca2PO4Cl. Although the ionic radii in chlorspodiosite are different from those in dibarium vanadate bromide, the structures are very similar to one another. The V atom is coordinated by four O atoms, forming a slightly distorted tetrahedron. The Ba atoms occupy two different sites and are coordinated by six O atoms and three or four Br atoms, depending on the site occupied.

1982 ◽  
Vol 37 (6) ◽  
pp. 688-694 ◽  
Author(s):  
Rolf M. Braun ◽  
Rudolf Hoppe

Abstract The new compound Rb2SnO2 was obtained as a light yellow powder by heating mixtures of the binary oxides (RbO0.48 + SnO, Rb: Sn = 2:1) under argon (sealed Ag cylinders, 600 °C, 3d). Subsequent annealing (550 °C, 8d and 500 °C, 17 d) led to light yellow transparent single crystals. Rb2SnO2 is extremely sensitive to moisture and decomposes into black products. It crystallizes orthorhombicly in the space group P212121-D42, with a = 5.761, b = 7.493, c= 11.167 Å, Z = 4, drö = 4.43 and dpyk = 4.46 gcm-3 , R= 11.8 and Rw = 12.0%. Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, and the Madelung Part of Lattice Energy, MAPLE, have been calculated. Isotypic K2SnO2 was obtained similarly as a brown powder, a = 5.579, b = 7.246, c = 16.744 Å.


1983 ◽  
Vol 38 (6) ◽  
pp. 661-664 ◽  
Author(s):  
Berthold Brazel ◽  
Rudolf Hoppe

Abstract Single crystals of HT-Li2PbO3 have been prepared by heating of mixtures of Rb2PbO3 and Li2O [Ag-cylinders, 600 °C, 100 d]. The structure determination [1005 symmetry independent l0(hkl), R = 5.85%, Rw = 5.35%, confirms space group C2/c with a = 548.60(16), b = 949.51(22), c = 1027.35(27) pm, β = 100.11(3)°, drö = 6.78 g · cm-3 , dpyk = 6.80 g · cm-3 , Z - 8. The NaCl-type structure variant is characterized by alter-nating layers of Li+ and Pb4+ /Li+ cations, which are all octahedrally coordinated. Effective Coordination Numbers, ECoN are calculated via Mean Fictive Ionic Radii, MEFIR.


1982 ◽  
Vol 37 (11) ◽  
pp. 1369-1374 ◽  
Author(s):  
Berthold Brazel ◽  
Rudolf Hoppe

For the first time single crystals of LT-Li2PbO3 have been prepared by decomposition of K2Li6[Pb2O8] [Incompletely closed Ag cylinders, sealed in Supremax-glass ampoule, vacuum, 690 °C, 100 d]. The structure determination [533Io(hkl); four-circle-diffractometer PW 1100, ω - scan, Mo - Kα, R = 4,86%, Rw = 4,93% confirms space group C2/c with a = 544.52(7), b = 926.12(7), c = 547,56(8) pm, β = 111.216(13)°, Z = 4, drö = 6.94 g · cm-3, dpyk = 6.89 g · cm-3. The NaCl-type structure variant is characterized by alternating layers of Li(2)+ and Li(l)+/Pb4+ cations. All atoms have octahedral coordination. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated.


2020 ◽  
Vol 76 (9) ◽  
pp. 1412-1416
Author(s):  
Günther J. Redhammer ◽  
Gerold Tippelt

Single crystals of KScP2O7, potassium scandium diphosphate, were grown in a borate flux. The title compound crystallizes isotypically with KAlP2O7 in space-group type P21/c, Z = 4. The main building block is an {ScP2O11}9– unit, forming layers parallel to (001). These layers are stacked along [001] via common corners of octahedral and tetrahedral units to span up large heptagonal cavities that host the potassium cations with a coordination number of 10. The P—O—P bridging angle increases with increasing size of the octahedrally coordinated M III cation, as do the K—O distances within a series of KM IIIP2O7 compounds (M III = Al to Y with ionic radii r = 0.538 to 0.90 Å).


1997 ◽  
Vol 52 (5) ◽  
pp. 663-668 ◽  
Author(s):  
B. Mertens ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of I RbCd4V3O12 and TlCd4V3O12 II have been prepared by solid state reactions in closed iron tubes. The compounds crystallize closely related to the Johillerite structure in the space group C62h- C2/c with I: a = 13.058(3); b - 13.528(3), c = 7 .0 6 0 (2 )Å , β = 114.88(2)°; II: a = 12.999(6), b = 13.527(7), c = 7.055(3) Å , β = 114.88(4)°, Z = 4. Special features are the loss of Cu2+ in order to gain an additional Cd2+ position. The crystal structure is discussed with respect to related compounds of the Johillerite type.


1994 ◽  
Vol 49 (7) ◽  
pp. 919-922 ◽  
Author(s):  
Hk. Müller-Buschbaum ◽  
S. Frenzen

Abstract Single crystals of (I): EuBeGd2O5, (II): Ca0,4Sr0,6BeSm2O5, (III): Ba0,25Ca0,75BeNd2O5 and (IV): Ba0.36Sr0.64BeNd2O5 were prepared by (I): plasma torch and (II)-(IV ): CO2-LASER technique. X-Rayo investigations lead to (I) monoclinic (space group C52h-P21/c, a = 7.126, b = 6.457, c = 9.394 Å , β = 90.40°) and (II)-(IV) orthorhombic symmetry (D162h-Pnma). (II: a = 9.454, b = 7.142, c = 6.490 Å; III: a = 9.508, b = 7.188, c = 6.531 Å; IV: a = 9.642, b = 7.295, c = 6.614 Å). In contrary to the phases M1-xM′xBeLn2O5, EuBeGd2O5 is characterized by an ordered distribution of Eu2+ and Gd3+ inside of the Kagomé network.


2015 ◽  
Vol 70 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

AbstractThe new compounds LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO were synthesized and their crystal structures were determined. Li[C(CN)3]·½ (H3C)2CO crystallizes in the orthorhombic space group Ima2 (no. 46) with the cell parameters a=794.97(14), b=1165.1(2) and c=1485.4(3) pm, while LiK[C(CN)3]2 adopts the monoclinic space group P21/c (no. 14) with the cell parameters a=1265.7(2), b=1068.0(2) and c=778.36(12) pm and the angle β=95.775(7)°. Single crystals of K[C(CN)3] were also acquired, and the crystal structure was refined more precisely than before corroborating earlier results.


2017 ◽  
Vol 72 (11) ◽  
pp. 765-774
Author(s):  
Daniel Rudolph ◽  
Sonja Laufer ◽  
Ingo Hartenbach

AbstractAttempts to synthesize Pr4Mo7O27 using Pr, Pr6O11 and MoO3 in a molar ratio of 8:6:77 led to a main product of scheelite-type Pr0.667[MoO4] and few single crystals of the triclinic A-type Pr6Mo10O39. The latter crystallizes in space group P1̅ (a=945.25(1), b=1058.49(2), c=1815.16(3) pm; α=104.149(1), β=95.220(1), γ=102.617(1)°, Z=2). Its crystal structure comprises six crystallographically independent Pr3+ cations, eight tetrahedral [MoO4]2− units, and one [Mo2O7]2− entity. The cations display coordination numbers of seven (1×) and eight (5×), while the [MoO4]2− tetrahedra are surrounded by five Pr3+ cations each. The [Mo2O7]2− anions exhibit a coordination environment of seven Pr3+ cations. The attempt to synthesize PrF[MoO4] using PrOF (from in situ thermal decomposition of PrF[CO3]) as reagent did not lead to the desired product but to monoclinic B-type Pr6Mo10O39. This slightly less dense modification compared to its triclinic analogue crystallizes in space group C2/c (a=1247.93(3), b=1989.68(6), c=1392.52 (4) pm, β=100.505(2)°, Z=4) with three crystallographically independent Pr3+ cations, four [MoO4]2− tetrahedra, and again one [Mo2O7]2− unit in the crystal structure. Thus, both Pr6Mo10O39 modifications are better described with the structured formula Pr6[MoO4]8[Mo2O7]. The coordination numbers around the Pr3+ cations are seven (1×) and eight (2×) while all four [MoO4]2− anions are again surrounded by five Pr3+ cations each. Six of the latter represent the coordination environment around the [Mo2O7]2− entities. Besides the thorough comparison of the crystal structures single crystal Raman spectra were recorded for both Pr6Mo10O39 phases.


2018 ◽  
Vol 74 (7) ◽  
pp. 1006-1009 ◽  
Author(s):  
Matthias Weil

Single crystals of Ba2K2Te2O9(dibarium dipotassium nonaoxidoditellurate), (I), Ba2KNaTe2O9(dibarium potassium sodium nonaoxidoditellurate), (II), and Ba2CaTeO6(dibarium calcium hexaoxidotellurate), (III), were obtained from KNO3/KI or KNO3/NaNO3flux syntheses in platinum crucibles for (I) and (II), or porcelain crucibles for (III). (I) and (II) are isotypic and are members of triple perovskites with general formulaA2[12co]A′[12co]B2[6o]B′[6o]O9. They crystallize in the 6H-BaTiO3structure family in space-group typeP63/mmc, with theA,A′,BandB′ sites being occupied by K, Ba, Te and a second Ba in (I), and in (II) by mixed-occupied (Ba/K), Ba, Te and Na sites, respectively. (III) adopts theA2[12co]B′[6o]B′′[6o]O6double perovskite structure in space-group typeFm-3m, with Ba, Ca and Te located on theA,B′ andB′′sites, respectively. The current refinement of (III) is based on single-crystal X-ray data. It confirms the previous refinement from X-ray powder diffraction data [Fuet al.(2008).J. Solid State Chem.181, 2523–2529], but with higher precision.


2019 ◽  
Author(s):  
Roberto Köferstein

Triclinic single crystals of Cu2(H2O)4[C4H4N2][C6H2(COO)4]·2H2O have been grown in anaqueous silica gel. Space group P-1 (Nr. 2), a = 723.94(7) pm, b = 813.38(14) pm, c = 931.0(2) pm, α = 74.24(2)°, β = 79.24(2)°, γ = 65.451(10)°, V = 0.47819(14) nm3, Z = 1. Cu2+ is coordinated in a distorted, octahedral manner by two water molecules, three oxygen atoms ofthe pyromellitate anions and one nitrogen atom of pyrazine (Cu—O 194.1(2)–229.3(3) pm;Cu–N 202.0(2) pm). The connection of Cu2+ and [C6H2(COO)4)]4− yields infinite strands,which are linked by pyrazine molecules to form a two-dimensional coordination polymer.Thermogravimetric analysis in air showed that the dehydrated compound was stable between175 and 248 °C. Further heating yielded CuO.


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